Thread-tapping concrete screws are screwed into holes drilled into a construction material, especially concrete, without the use of a plug. Here, the diameter of the drilled hole is greater than the core diameter of the screw and smaller than the outer diameter of the screw with the thread. Consequently, as the screw is being screwed in, especially by means of an impact driver, the screw works its way into the construction material in such a way that the thread taps or cuts a mating thread into the construction material. Therefore, the screw itself cuts the thread or mating thread needed for the required positive fit between the thread and the construction material.
European patent specification EP 1 795 768 B1 discloses a thread-tapping screw, especially a concrete screw, having a thread and a thread root, whereby the thread has interruptions that form cutting edges, the thread root is conically shaped in a front section of the screw, and the screw has a groove that runs in a lengthwise direction of the screw, that passes through the thread and that forms the interruptions, and that is deeper than the height of the thread, so that it extends into the thread root, whereby the depth of the groove decreases from the front end of the screw towards the end of the conical section of the thread root.